Hello, I have a question regarding checking for errors that occur when calling sqlite3_column_*.
From this manual page: https://sqlite.org/c3ref/column_blob.html it seems that the only error that could occur (other than programmer error, like out-of-bounds column index or calling it after something other than SQLITE_ROW) is memory allocation error. That page says that, in the event of memory allocation error, an appropriate default value is returned and then sqlite3_errcode will return SQLITE_NOMEM. From this manual page: https://sqlite.org/c3ref/errcode.html it states explicitly that, if the most recent call failed, then sqlite3_errcode returns the error code, but if the most recent call succeeded, then the return value is undefined. So how do I check if sqlite3_column_int failed due to memory allocation error? If sqlite3_column_int returns zero, I don’t know whether it succeeded or failed. In the event that it succeeded, then the return value from sqlite3_errcode is undefined. So even if sqlite3_column_int returns zero and sqlite3_errcode returns SQLITE_NOMEM, it could be that an allocation failed, but it could just as well be that the actual column value was zero and sqlite3_errcode randomly decided to return SQLITE_NOMEM because the return value is undefined because sqlite3_column_int succeeded. I discovered from inspecting the source code (and then confirmed by testing) that if an sqlite3_column_* function fails, then the next sqlite3_step call will *also* fail with SQLITE_NOMEM (and that’s detectable because sqlite3_step returns a result code as its return value), but that doesn’t seem to be documented anywhere in the manual at all. So what’s the proper way to check for errors in these functions? Thanks! -- Christopher Head
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